Amnesia: The Dark Descent Walkthrough: Entrance Hall to the Refinery

As soon as you get out of the Laboratory, run! Turn left and go back up
to the main Entrance Hall. Before we enter the Refinery, let’s grab some
extra stuff first.

From the center of the Entrance Hall where the circle is, there’s another
hall that we haven’t visited yet. Check out this hall. On the left wall
is a chest. Open it to get a tinderbox and a bottle of oil. Proceed down
the hall and near the end, the last shelf has three boxes near it. Move
the boxes to reveal a hidden bottle of oil.

You can try to open the doors at the end, but suddenly those red organic
stuff will cover it. Go back to the main Entrance Hall and then move down
the stairs near the circle. Go through the door and we’re back to the place
that the red organic stuff is blocking. Open your inventory, double click
on the Pot of Acid, and then use it on the red organic matter. Watch it
dissolve! Now move along and go through the door.